bug#48724: Code collapsing and outline headings for elisp

[Juri Linkov]

> I suggest that emacs-lisp-mode does code collapse (show/hide) by default.
> Then outline-minor-mode does additional headings in the form
>
> ;;; Heading 1
> ;;;; SubHeading
> ;;;;; SubSubHeading
>
> ;;; Heading 2
>
> outline-minor-mode would then be made to collapse sections of code between
> headlines.
>
> This means that a headline hide could hide a number of variable and function
> definitions that belong together.

Recently we changed the outlines of emacs-lisp-mode in 
https://debbugs.gnu.org/46878
So this is already fixed.